Products

AVT constantly strive to identify the most suitable VFC for all flow control situations. AVT’s devices are normally fabricated in 10 gauge (3mm) Grade 304 stainless steel to all the relevant British Standards and match the specification of the perceived market leaders. Certificates of Conformity can be supplied with each unit, if required. Stainless steel does not corrode and is highly resistant to abrasion. Life expectancy of each unit is likely to exceed that of the system into which it is installed. Following installation there is little need for maintenance. They come equipped with a Draindown/Bypass mechanism which is remotely operated from ground level. In the unlikely event of a blockage occurring in the inlet or outlet of the VFC the mechanism allows draindown of the system without the need for expensive overpumping or bypass penstocks and pipework, unlike other makes of VFCs which can only bypass a blockage in the inlet.

Vortex Flow Controls

The AVT vortex flow control is a self-activating flow control device which induces a vortex motion in the flow to control the rate at which water is allowed to enter downstream drainage systems. The energy inherent in the water flow is harnessed to generate the vortex and hence has no need of external energy requirements. The flow control itself has no moving parts.

The VFC has a superior hydraulic performance when compared to conventional flow controls such as orifice plates, throttle pipes and penstocks. With outlet diameters up to 400% larger than conventional flow control devices, the risk of blockage is minimised. VFCs have a unique head/flow characteristic with a distinctive “S” shaped curve with high flush and kick-back flow points. This characteristic can reduce storage volume requirements thereby lowering project costs.

Applications

Control of surface water runoff from:

Housing

Industrial developments

Infrastructure developments

Land drainage

As part of flood and pollution alleviation schemes within:

Existing sewerage systems

River networks

Flow balancing in:

New and existing sewerage systems

Sewerage treatment works

Potable water treatment plants

Control of pass-on flows from:

Combined sewer overflows

Storage tanks

Reservoirs

Swales

Advantages

Less prone to blockage due to outlet cross-sectional areas of up to 4 times larger than:

Orifice plates

Penstocks

Throttle pipes

Unique Draindown/Bypass release mechanism which also allows:

Downstream access for maintenance

Drain down

Easy operation from ground level

Other features:

No moving parts

Self-activating

No external energy requirements

Resistant to abrasion and corrosion

Individually designed

Savings in time and labour due to flexible installation methods
unique head/flow relationship can produce savings in storage volumes

Models

SW & SSW Flow-range: 1–200 1/s

Normally only used in surface water systems as a sump is generally required due to the outlet being higher than the inlet.

CB2 & CB3 Flow range: 3 – 4000 1/s

Can be used in surface water systems when Models SW and SSW are physically too large. Also used in foul and combined applications.

CS1 & CS2 Flow range: 3 – 4000 1/s

Used in place of models CB2 and CB3 when their physical size cannot be accommodated.

Each unit is built to individual size and will vary from its suitability.

Additional optional features

Designed to save time, labour, materials and cost

Tailor-made Mounting Plate

Eradicates the need for an in-situ concrete mounting block in circular manholes

In-Built Overflow System

Avoids the problems associated with constructing in-situ overflows

Sectionalised Components

Allows larger units to be retro-fitted into existing manholes and chambers

Vortex Inhibitor

Provides the ability to significantly increase the flow through the control for a small increase in head.

Installation

VFCs are reasonably easy to install. AVT will provide full installation instructions with every unit ordered. Click here for online installation guide.

Installation instructions for SW model VFC

STEP 1

Where appropriate, construct mounting block to the dimensions indicated on Installation Drawing.

STEP 2

Disconnect the stainless steel wire rope from the draindown/bypass disc valve. Offer up the flow control to the manhole outlet pipe in the mounting block with the upper edge of the mounting plate horizontal and with the flow control outlet pipe inserted flush with the invert of the manhole outlet pipe. Mark the positions of the holes in the mounting plate onto the outlet pipe wall. Remove the flow control.

Reposition the flow control over outlet pipe complete with the neoprene sealing gasket in place and correctly aligned with the flow control. Apply nuts and tighten to ensure a watertight seal. Ensure that the bypass door does not foul on the mounting block.

(Note: any apparent deformation in the mounting plate will be straightened out as the nuts are tightened.)

Attach the eyelet bolt to the roof slab or brickwork just below the manhole cover so that it can be easily accessed from ground level. Thread the stainless steel wire rope through the eyebolt and reconnect the lower end to the draindown/bypass disc valve. Ensure that the wire rope does not foul the intake to the vortex flow control.

Installation instructions for model CB2/T2 VFC

STEP 1

Cast the in-situ concrete mounting block as shown on Installation Drawing. Form chase 75mm deep by 50 mm wide to accommodate the lower edge of the mounting plate.

STEP 2

Disconnect the stainless steel wire rope from the draindown/bypass mechanism. Offer up the flow control to the manhole outlet pipe in the mounting block with the upper edge of the mounting plate horizontal and with the invert of the flow control outlet level with the invert of the manhole outlet pipe. Mark the positions of the holes in the mounting plate onto the mounting block. Remove the flow control.

Reposition the flow control over outlet pipe complete with the neoprene sealing gasket in place and correctly aligned with the flow control. Apply nuts and tighten to ensure a watertight seal.

(Note: any apparent deformation in the mounting plate will be straightened out as the nuts are tightened.)

STEP 5

Form benching to direct flows into the inlet of the flow control, making sure that the benching does not foul the bypass/draindown mechanism.

STEP 6

Attach the eyelet bolt to the roof slab or brickwork just below the manhole cover so that it can be easily accessed from ground level. Thread the stainless steel wire rope through the eyebolt and reconnect the lower end to the draindown/bypass disc valve. Ensure that the wire rope does not foul the intake to the vortex flow control

Product F.A.Q s

Q. How much maintenance will a Vortex Flow Control require?What happens if they get blocked?

A. Very little. As there are no mechanical or moving parts needed the only maintenance likely to be needed, will be clearing blockages. To make your life easier we design all our products with a bypass door, which can be opened using a wire rope pulley, which we provide that will be connected to the top of the manhole, so you won’t even have to get your feet wet. This is a sufficient enough method to unblock most blockages easily.

Q. How long will they last?

A. A very long long long time! Because of the high grade 316 stainless steel used these things are made to last and will withstand any abuse from the water flow and any debris. These units will easily outlive the actual sewer system they are in.

Q. Are they easy to install/ do I need a specialist to do the job for me? How long will it take to install?

A. The units are simple to install, they can be fitted by any of the ground workers and will not take any longer than it is to drill a number of holes into the wall and bolt the unit in. This of course all depends on the size of the unit as lifting gear/ machinery may be needed. For a further detailed explanation see the Installation Instruction Guide.

Q. Do I need to buy anything additional for the VFC to work?

A. No! We will provide you with absolutely everything you will need, including fixing bolts and drill bits.

Q. Can the VFC be used in any chamber design?

A. Yes, as long as the chamber is large enough to take one! To ensure you get the maximum efficiency in relation to the design of the chamber the unit will be going in to, we will provide you with the most suitable VFC for your situation. You may need to make small changes to the design of the chamber to help increase the efficiency of the VFC but this will not be anything drastic nor to time consuming.